Aims: This study aims to determine the profile of patients as well as identify predisposing factors of patients presenting with low back pain (LBP) in Irrua Specialist Teaching Hospital Irrua, Edo state of Nigeria. Subjects and Methods: A retrospective study in which case records of all newly diagnosed patients with LBP from January 2011 to December 2013 were analyzed and the following data were extracted: demographic indices, duration of symptoms before presentation, predisposing factors, etc. Results: Within the study periods, 3120 patients presented at the orthopedic clinic, out of these, 101 patients had LBP. The prevalence rate was 3.24%. Median age was 58 years. Peak age incidence was 61–70 years. Age range 13–84 years. Male:female 1:1. Most affected occupational age groups were farmers 24 (23.76), traders 23 (22.77%), and civil servants 17 (16.83%). The most common predisposing factors to LBP were trauma to the lower back 23 (22.8%), lifting of heavy objects 11 (10.9%), and obesity 8 (7.9%). Spondylosis was the leading Diagnosis. L4/L5, L5/S1 were the most affected segments The percentage of patients presenting as acute, subacute, and chronic LBP were 28.7%, 9.9%, and 61.4%, respectively. Conclusions: Chronic LBP rank the highest among patients with LBP in our environment. Middle and elderly age brackets were other highlights. Trauma, lifting of heavy weights and obesity were notable predisposing factors.

Keywords:Epidemiology, low back pain, Nigerian, suburban, tertiary

How to cite this article:Edomwonyi EO, Ogbue I A. Epidemiology of low back pain in a suburban Nigerian tertiary centre. Niger J Surg Sci 2017;27:20-5

Low back pain (LBP) can be defined as pain limited to the region between the lower margins of the rib cage and the gluteal creases. It can also be defined as pain experienced in the low back region.

It is the most prevalent musculoskeletal condition and one of the most common causes of disability in orthopedic practice in developed nations.[1]

LBP is such a frequent cause of disability in the community that it has become almost a disease in itself. Increase in age is associated with an increase in musculoskeletal diseases such as arthritis, osteoporosis, spinal disc degeneration which sometimes present as LBP.

LBP can be psychologically and physically debilitating; thus, counseling and support are often welcomed by the patients. Patients with LBP may despair of finding a cure for their trouble and may develop affective and psychosomatic ailments which subsequently become the chief focus of attention. This illness behavior is self-perpetuating and self-justifying since it is usually accompanied by nonorganic physical signs such as pain and tenderness of bizarre degree and distribution, sensory and motor abnormalities which do not fit known anatomical and physiological patterns.[2]

Gender influences on pain and analgesic use have become a topic of tremendous scientific and clinical interest in the past decade. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and current human findings indicate greater pain sensitivity among females compared with males for most pain modalities.[3]

In a study spanning 17 countries across 6 continents, the prevalence of any chronic pain condition was higher among females (45%) than males (31%), and females had a higher prevalence of depression comorbid with chronic pain than males.[4]

There are a number of ways to classify LBP with no consensus as to the best of methods.[5]

There are 3 types of LBP by cause: nonspecific or mechanical back pain. This includes musculoskeletal strains and sprains, herniated discs, compressed nerve roots, degenerated discs, or joint disease. These underlie 90% of cases.[6] Specific or nonmechanical pain are those due to tumors, inflammatory conditions, infections, fractures, etc. Referred pain from internal organs (gallbladder disease, kidney stones, and infections, aortic aneurysms).[6]

Rarely, LBP may result from systemic or psychological problems such as fibromyalgia and somatoform disorders.[6]

Most painful conditions of the lumbar spine affect the two lower lumbar motion segments (L4/L5 and L5/S1) which degenerate earlier.[7] Physical stress which is maximum at these segments is the proximate cause of acute disc herniation, especially in the presence of degenerative changes of the nucleus pulposus.[4]

It is generally assumed that LBP prevalence in Africa is comparatively lower than in developed countries. However, recent findings suggest that LBP prevalence among Africans is rising and is of concern.[4] The range of LBP point prevalence of 10%–59% in Africans [7] and 12%–33% among Western societies [8] negates any assumptions that LBP prevalence is lower in developing world than developed societies; and supports the global burden of disease studies which predicts that the greatest increases in LBP prevalence will be in developing nations.[9]

The economic, societal, and public health effects of LBP appear to be increasing. LBP incurs billions of dollars in medical expenditure each year [10] and the USA; it costs the community 100 billion dollars annually. LBP is a major cause of disability, expense from work-related conditions, and absence from work. This results in enormous economic burden on many world communities. This economic burden is of particular concern in poorer nations of Africa where the already limited and restricted health-care funds are directed toward epidemics and often misappropriated.

LBP was branded the “litigation symptom” in the early 20th century because it was the singular most important and common component of the worker's compensation costs. The frequency and costs of the use of health services, including the rate of lumbar spine surgeries, and the sickness days are increasing enormously worldwide

LBP is considered as much a problem of a patient's response to pain as a problem of the back itself. It can impose other less tangible costs on the patients who had been noted to have problems with functional and social activities, relationships, emotional well-being, and even socioeconomic status.

Bad posture plays a very significant role in the genesis of disc degeneration and disease. So much is the contribution of bad posture toward this problem that one can categorically conclude that LBP is all about disc degeneration predisposed by bad posture.[11]

The course of LBP in an individual's lifetime is often recurrent, intermittent, or episodic.

The strongly associated risk factors for the development of LBP includes previous back pain, Increasing age up to 5–6th decade, prolonged sitting, or standing (static work posture) heavy physical work especially with repetitive lifting, depression, job dissatisfaction and emotional distress, heavy physical work especially with repetitive lifting, awkward, bending positions for long periods.[12],[13]

Other factors which are weakly associated with the risk of LBP are gender, trunk length, lumbar mobility, and radiographic structural abnormalities of the spine such as listhesis, sacralization, osteoporosis, and osteoarthritis.

The lack of clarity on the causes, treatments, and factors contributing to LBP has led to fear that some workers may exploit and abuse the workers' compensation scheme to demand vast claims. Back pain disability claims increase during periods of economic recession; and factors such as drug abuse, job dissatisfaction, pursuit of disability compensation, and litigation involvement may be associated with persistent unexplained LBP. It is thus important to know as much about the man who has the pain as it is to know about the pain the man has.

In this era of escalating health-care costs, we need to look at the associated factors that affect the economic impact of LBP in the society and ways to improve the treatment efficacy.

Data on this subject in my institution are nonexistent, hence, this study was done so as to determine the profile of patients as well as identify associated factors of LBP as they present Irrua Specialist Teaching Hospital (ISTH) irrua and see if they conform to what obtains in other regions.

Subjects and Methods

This is a retrospective study carried out in the Department of Orthopaedics and Trauma of ISTH Irrua, Edo State of Nigeria.

ISTH Irrua is a tertiary health institution and a referral center for most health institutions in South-South Nigeria.

Case records of all patients with LBP presenting at our center between January 2011 and December 2013 (This was the readily available data at the time of this study) were retrieved from the medical records department and were reviewed. The following data were extracted; demographic indices, duration of symptoms before presentation, predisposing factors, clinical diagnosis, diagnostic modalities, spinal level of involved vertebrae, neurologic deficits, and treatment given. Patients with vertebra fractures, spinal cord injuries were excluded.

Out of the 3120 patients that presented at the orthopedic outpatient clinic over the period, 101 had LBP giving a prevalence rate of 3.24%. Median age was 58 yrs. Peak age incidence was 61–70 years [Table 1]/[Figure 1] age range 13-84 years. Male:female ratio 1:1.

The review of research publications on LBP suggests that most research has been conducted in the developed nations, where little racial heterogeneity exists. The studies done on LBP in the African Continent is very limited, though the literature on the epidemiology of LBP in Africa is accumulating. The prevalence of LBP in the Nigerian populace is not known with certainty. Our prevalence rate was 3.24%.

The peak age incidence of LBP in this study was 61–70 years. Ogunbode et al.[12] reported 51–60 years while Eyichukwu and Ogugua [13] and Omokhodion [14] reported a variant, 31–40 years. Degenerative changes in the spine occasioned by aging as well as the cumulative effect of excessive occupational/daily activities associated with early productive life may account for this striking observation. Three of the patients in our series were teenagers and had no history of associated trauma. However, backpack overloaded with school books and supplies can strain the back and cause muscle fatigue.[15]

Those in the fourth decade were the next most commonly affected [Table 1]. The widespread introduction of information technology systems in Nigerian schools and civil/public service may be another factor that is contributing significantly to sedentary lifestyle and poor postural habit which contribute to increasing the prevalence of LBP among young Africans.

The male to female ratio in our study is 1:1. Many authors have reported point prevalence, and severity of back pains are higher among females than males.[16],[17] Omokhodion [14] report was at variance. Our community is an agrarian type. Socioeconomic factors compel women to engage in farming so as to assist or augment the effort of the men in providing for the family.

The effect of pregnancy on the prevalence of LBP apparently played a significant role in the higher prevalence in women than men in this study. About 76% of our study populations are married, and this may explain the influence of pregnancy in this predominantly female study population. Studies have shown that pregnancy is one of the risk factors that increase the likelihood of developing LBP in females.[18]

The principal occupation of patients was farming 24 (23.76%) closely followed by trading 23 (22.77%), then civil servants 17 (16.83%). This underscores the principal occupation and source of income for semi-urban/rural dwellers. Apart from farmers, these are essentially sedentary workers. The risk factors that increase the likelihood of back pain includes aging, poor general health, physically demanding occupations, participation in sports that involve twisting the back, a sedentary lifestyle, previous back injury, depression, pregnancy, smoking, obesity, poor posture, bone and joint disease.[19] The lack of awareness of back protection strategies is relatively high among civil servants. There is also a dearth of legislation to support workers suffering LBP to ensure they receive optimal rehabilitation and support. In contrast, in Western societies, legislation to promote spinal health protects workers from lumbar spine injuries is in place and monitored by governmental bodies.[20]

About 64% of patients were involved in sedentary occupations, and 88% of them were more than 30 years of age. Eyichukwu and Ogugua [13] reported a similar finding in Enugu, Nigeria. Attempts at meeting up with family demands by people in this age bracket prevent them from engaging in regular exercises which puts them at risk of developing LBP. Sitting upright increases the pressure in the lumbar disc by 50% compared to standing erect, and sitting slumped doubles this pressure.

Trauma topped the list of identifiable associated factors, 23 patients (22.77% of cases). Some authors [14],[21],[22] had a similar observation. In 53 patients, none was identified. It is probable that risk factor (s) may be present, but no deliberate or conscious effort was made to search for them.

Etiologically, 83 (82.1%) of patients with LBP were mechanical. This compared with 82% and 80% reported by Hills.[23] and Eyichukwu and Ogugua,[13] respectively. Ahudjo's finding [24] was not different.

Lumbosacral spondylosis was the most common, 44 patients (44% of cases). This is at variance with Andersson [11] and Irurhe et al.[25] reports. They reported disc abnormalities instead. The reason for the difference is not very clear. It may be racial. Plain X-rays is the common and cheaper modality of radiological evaluation in our environment. About 81.2% of patients actually did it. It displays bony structures and alignment, while CT/MRI evaluates neural structures, cord, and disc.

About 28.7% of the patients in our series presented as acute LBP (<4 weeks), 9.9% as subacute LBP (4 weeks– 12 weeks) while 61.4% presented as chronic LBP (>12 weeks). It is usual practice for the majority of our patients to delay presentation to orthodox medical practitioners in tertiary health centres like ours when self-medications, consultation of native herbal practitioners, and spiritualist have failed.

About 21 (20.8% of cases) patients had associated radiculopathy, commonly to L5 and S1 segmental dermatomes. Seventy-six percent of the radicular pain occurred in patients presenting as chronic LBP, especially those whose symptoms had lasted more than a year.

In 7 (6.9%) patients, no definitive diagnosis was made after investigations. The reasons for this high percentage of LBP diagnostic enigma in Irrua is possibly linked to high cost and very limited availability of specialized diagnostic tools as MRI and CT scan. Eyichukwu and Ogugua reported 9%. None of the cases where CT/MRI was requested could afford/assess these diagnostic facilities. Possibly, these patients may have primary spinal tumors which cannot be diagnosed readily by other modalities aside from CT scan and MRI. The group will also comprise patients presenting with depression, psychosomatic disorders as tension myositissyndrome, and those with early seronegative spondyloarthritides, nerve root stenosis and referred pains.

Waddell [26]et al. had demonstrated clearly that psychosomatic problems contribute significantly to the development of LBP and had developed a method of identifying such cases.

The most affected spinal segments in our study are the L4/L5 and L5/S1 motion segments. These are the weakest segments of the lower back. This finding corroborates the findings of other studies which demonstrated that the lower two lumbar motion segments are the most commonly affected in spondylosis and intervertebral disc degeneration [7],[11],[18] and degenerative spondylolisthesis.[26] The stress on the lumbar spine is maximal at L4 which has relatively small transverse process, less ligamentous support and more mobility than the adjourning vertebrae. The excess stress results in advanced degenerative charges in the discs and facet joints.

Conclusions

Majority of our patients presenting with LBP had Chronic LBP with an equal male to female ratio. Farmers and those in the middle and elderly age brackets constituted the bulk. Trauma, lifting and obesity were notable associated factors while not undermining the role of sedentary lifestyle. Mechanical type topped the list with spondylosis, the most common variety. L4/L5 and L5/S1 segments were the most affected segments.

A thorough understanding of the activities of daily living, as well as social lifestyle of our patients, would assist in identifying the associated factor (s).

WHO Scientific Group on the Burden of Musculoskeletal Conditions at the Start of the New Millennium. The burden of musculoskeletal conditions at the start of the new millennium. World Health Organ Tech Rep Ser 2003;919:i-x, 1-218.